There are many induction modes for a touch screen, such as optical, microwave, resistance, capacitance induction modes, wherein the capacitance induction mode is most widely used. The capacitance induction mode includes a self-capacitance induction mode and a mutual capacitance induction mode. Compared to the self-capacitance induction mode, the mutual capacitance induction mode has advantages of strong anti-interference ability, high sensitivity, realizing multi-touch ability and good recognition ability etc., thus the mutual capacitance induction mode has become the mainstream induction mode of a touch screen now.
Currently, there are two types of touch screen of the mutual capacitance induction mode: In-Cell touch screen and On-Cell touch screen. In an In-Cell touch screen, a touch induction electrode and a touch drive electrode are provided inside a display panel. In order to achieve compactness, at present, a design of sharing a certain signal electrode between display and touch is used in the In-Cell touch screen, for example, a common electrode used for displaying is also used as a touch drive electrode for touching. However, in an On-Cell touch screen, a touch induction electrode and a touch drive electrode are provided outside or on an outer surface of a display panel. As the electrode used for displaying and the electrode used for touching are provided and controlled separately, the On-Cell touch screen has an advantage of no mutual interference between display and touch. However, by contrast, for the In-Cell touch screen, as a certain signal electrode is shared and time-division multiplexed, there is no need for additional procedures to prepare the touch screen, and the aperture ratio and transmittance of display pixels are almost not affected. Thus, the In-Cell touch screen has great application prospect.
As shown in FIGS. 1 and 2, a touch screen of the mutual capacitance induction mode in the prior art comprises a touch substrate comprising an insulation layer, a common electrode layer, and a common electrode signal line 1 and a plurality of touch drive electrode signal lines 2 provided in the same layer, wherein, the insulation layer is provided between the common electrode layer and the common electrode signal line 1 and the touch drive electrode signal lines 2. The common electrode layer comprises a plurality of common electrodes 300, a plurality of touch drive electrodes (touch drive sub-electrodes 200 in each column in FIGS. 1 and 2 constitute one touch drive electrode) which are multiplexed, and a common electrode connection strip 100 for connecting the common electrodes 300, wherein, the common electrodes 300 and the touch drive electrodes are intersected and insulated with each other, each of the touch drive electrodes comprises a plurality of touch drive sub-electrodes 200, the common electrode connection strip 100 is connected with the common electrode signal line 1 through a plurality of first via-holes 101 penetrating through the insulation layer (as shown in FIG. 1), or a plurality of third via-holes 301 are provided at positions of the insulation layer corresponding to positions of the common electrodes 300, the third via-holes 301 are used for connecting the common electrodes 300 and the common electrode signal line 1 (as shown in FIG. 2), each of the touch drive sub-electrodes 200 is connected with one of the touch drive electrode signal lines 2 through a second via-hole 201 penetrating through the insulation layer, the touch drive sub-electrodes 200 of different touch drive electrodes are connected with different touch drive electrode signal lines 2.
The inventor found that there are at least following problems in the prior art: in order to avoid a problem of delay, a plurality of via-holes are formed in the insulation layer corresponding to the common electrode connection strip 100 or the common electrode connection strip 100 and the common electrodes 300 for connecting the common electrodes 300 and the common electrode signal line 1. The objective of forming the plurality of via-holes is to reduce resistances of the common electrodes, but each of the touch drive sub-electrodes 200 is connected with the touch drive electrode signal line 2 only through one second via-hole 201 in the insulation layer corresponding thereto, thus, for a whole touch substrate, the distribution of the via-holes are great non-uniform, thereby the abilities of the common electrode signal line 1 and the touch drive electrode signal lines 2 to reflect light are inconsistent, and under influence of an electric field, display of pictures on the touch screen is not uniform.